Multi-core fiber for a multi-spot laser probe

ABSTRACT

The present disclosure relates to a multi-core optical fiber cable (MCF). In some embodiments, an MCF comprises a plurality of cores surrounded by a cladding and a coating surrounding the cladding, wherein a refractive index of one or more of the plurality of cores is greater than a refractive index of the cladding. The MCF further comprises a probe comprising a probe tip coupled with a distal end of the MCF and a lens located at a distal end of the probe tip. In some embodiments, the lens is configured to translate laser light from the distal end of the MCF to create a multi-spot pattern of laser beams on a target surface and a distal end of the MCF terminates at an interface with the lens.

PRIORITY CLAIM

This application:

(a) is a continuation application of U.S. patent application Ser. No.16/218,333 titled “Multi-Core Fiber for a Multi-Spot Laser Probe” whichwas filed on Dec. 12, 2018 whose inventors are Chenguang Diao, MarkHarrison Farley, Alireza Mirsepassi, Ronald T. Smith, and DeanRichardson which is hereby incorporated by reference in its entirety asthough fully and completely set forth herein, and

(b) claims the benefit of priority of U.S. Provisional Application Ser.Nos. 62/597,550, 62/622,299, 62/630,865, and 62/598,653 (U.S. patentapplication Ser. No. 16/218,333 claimed the benefit of priority ofProvisional Application Serial Nos. 62/597,550, 62/622,299, 62/630,865,and 62/598,653).

FIELD

The present disclosure relates to a multi-spot laser probe, and morespecifically to systems and methods for delivering multi-spot laserlight beams via a surgical probe having a multi-core optical fibercable.

BACKGROUND

In a wide variety of medical procedures, laser light is used to assistthe procedure and treat patient anatomy. For example, in laserphotocoagulation, a laser probe is used to cauterize blood vessels atlaser burn spots across the retina. Certain types of laser probes burnmultiple spots at a time, which may result in faster and more efficientphotocoagulation. Some of these multi-spot laser probes split a singlelaser beam into multiple laser beams that exhibit a laser spot patternand deliver the beams to an array of optical fibers that exhibit acorresponding fiber pattern. Typically, the fibers should be tightlypacked so that the fiber pattern matches the laser spot pattern.Moreover, the laser spot pattern should be accurately aligned with thefiber pattern.

In addition to cauterizing blood vessels at the laser burn spots, thelaser may also damage some of the rods and cones that are present in theretina that provide vision, affecting eyesight. Since vision is mostacute at the central macula of the retina, the surgeon arranges thelaser probe to generate laser burn spots in the peripheral areas of theretina. In this fashion, some peripheral vision may be sacrificed topreserve central vision. During the procedure, the surgeon drives theprobe with a non-burning aiming beam such that the retinal area to bephotocoagulated is illuminated. Due to the availability of low-power redlaser diodes, the aiming beam is generally a low-power red laser light.Once the surgeon has positioned the laser probe so as to illuminate adesired retinal spot, the surgeon activates the laser through a footpedal or other means to then photocoagulate the illuminated area. Havingburned a retinal spot, the surgeon repositions the probe to illuminate anew spot with the aiming light, activates the laser, repositions theprobe, and so on until a desired number burned laser spots aredistributed across the retina.

For diabetic retinopathy, a pan-retinal photocoagulation (PRP) proceduremay be conducted, and the number of required laser photocoagulations forPRP is typically large. For example, 1,000 to 1,500 spots are commonlyburned. It may thus be readily appreciated that if the laser probe was amulti-spot probe enabling the burning of multiple spots at a time, thephotocoagulation procedure would be faster (assuming the laser sourcepower is sufficient). Accordingly, multi-spot/multi-fiber laser probeshave been developed and described in U.S. Pat. Nos. 8,951,244 and8,561,280, which are hereby incorporated by reference in their entirety.

Vitreoretinal procedures also benefit from illumination light beingdirected into the eye and onto retinal tissue. Vitreoretinal surgeonsoftentimes use a laser probe for delivering the laser aiming beams andlaser treatment beams and also use an additional instrument fordirecting an illumination light beam onto the retinal surface in orderto view patient anatomy.

SUMMARY

According to one embodiment, the present disclosure is directed to amulti-spot laser probe that includes a probe body shaped and sized forgrasping by a user; a probe tip that includes a cannula configured forinsertion into an eye; a graded-index (GRIN) lens disposed in thecannula at a distal end portion thereof; and a multi-core optical fibercable (MCF) extending at least partially through the cannula. The MCFmay include a plurality of cores formed of germanium-doped silica; acladding formed of fused silica; a coating surrounding the cladding; anda distal end disposed at an interface with the GRIN lens. The claddingmay surround the plurality of cores. A refractive index of one or moreof the plurality of cores may be greater than a refractive index of thecladding. A portion of the coating may be omitted from a length of thedistal end of the MCF, and the GRIN lens may be configured to translatelaser light from the distal end of the MCF to create a multi-spotpattern of laser beams on a target surface.

Another embodiment is directed to a multi-spot laser probe that includesa MCF that includes a plurality of cores surrounded by a cladding and acoating surrounding the cladding and a probe. The probe may include aprobe tip coupled with a distal end of the MCF. The multi-spot laserprobe may also include a lens located at a distal end of the probe tip.The lens may be configured to translate laser light from the distal endof the MCF to create a multi-spot pattern of laser beams on a targetsurface. A distal end of the MCF may terminate at an interface with thelens. A refractive index of one or more of the plurality of cores may begreater than a refractive index of the cladding.

A further embodiment is directed to a method of applying a multi-spotlaser beam pattern. The method may include generating a laser light beamby a laser source; collimating the laser light beam; directing thecollimated laser light beam to a diffractive optical element (DOE)configured to create a multi-spot laser pattern of laser light beams;and focusing the multi-spot pattern of laser light beams into aninterface plane of a proximal end of a MCF. Each of the laser lightbeams in the multi-spot laser pattern of laser light beams may betransmitted into one of a plurality of cores of the MCF. The laser lightbeams may be propagated along the cores of the MCF. The plurality ofcores may be surrounded by a cladding, and the cladding may besurrounded by a coating. A refractive index of each of the plurality ofcores may be greater than a refractive index of the cladding, and aportion of the coating may be omitted from a length of a distal end ofthe MCF. The method may also include transmitting the multi-spot patternof laser light beams to the distal end of the MCF and directing themulti-spot pattern of laser light beams through a lens at a distal tipof a surgical probe.

The various embodiments of the present disclosure may include one ormore of the following features. The plurality of cores may form a 2×2array that may be configured to match a 2×2 multi-spot pattern from adiffractive optical element (DOE) of a laser system. The distal end ofthe MCF may abut a GRIN lens with positive pressure at the interface.The distal end of the MCF may be separated from a GRIN lens by an airgap. A length of the portion of the coating may be removed from the MCF,and that length may be in a range of 0.5 mm to 5.0 mm extendingproximally from the distal end of the MCF. The length of the portion ofthe coating removed from the MCF may be in a range of 1.0 mm to 3.0 mmextending proximally from the distal end of the MCF.

The various embodiments of the present disclosure may also include oneor more of the following features. A portion of the coating may beomitted from a length of the distal end of the MCF. A length of thecoating omitted from a length of the distal end of the MCF may be in arange of 1.0 mm to 3.0 mm. The plurality of cores may form a 2×2 arraythat is configured to match a 2×2 multi-spot pattern from a diffractiveoptical element (DOE) of a laser system. The lens may include a GRINlens, and the distal end of the MCF may abut the GRIN lens with positivepressure. The lens may include a GRIN lens, and the distal end of theMCF may be separated from the GRIN lens by a gap. The probe tip mayinclude a cannula configured for insertion into an eye. The distal endof the MCF and the lens may be disposed in the cannula. A portion of thecoating at the MCF may be omitted, thereby improving power handlingcharacteristics of the multi-spot laser probe. The lens may be locatedat a distal end of the probe tip may include a GRIN lens. The distal endof the MCF may abut the GRIN lens with positive pressure. The distal endof the MCF may be separated from the GRIN lens by an air gap. Thecoating may include a polyimide coating. The plurality of cores mayinclude germanium-doped silica. The cladding may include fused silica.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present technology, itsfeatures, and its advantages, reference is made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates an example system for generating a multi-spot patternof laser light beams for delivery to a surgical target, in accordancewith a particular embodiment of the present invention.

FIG. 2 illustrates an example multi-spot laser probe, in accordance witha particular embodiment of the present invention.

FIGS. 3 and 4 illustrate an end of an example multi-core optical fibercable (MCF) for use with non-illuminating multi-spot laser probes, inaccordance with a particular embodiment of the present invention.

FIG. 5 shows an end of an example MCF for use with illuminatingmulti-spot laser probes, in accordance with a particular embodiment ofthe present invention.

FIG. 6 is a partial cross-sectional detail view of a distal end portionof an example multi-spot laser probe tip, in accordance with aparticular embodiment of the present invention.

FIGS. 7A-7F2 show various aspects of multi-spot/multi-fiber laser probesin comparison with aspects of MCF laser probes to highlight variousadvantages and benefits of the multi-core fiber cable laser probes, inaccordance with a particular embodiment of the present invention.

FIG. 8 illustrates example operations performed by a surgical lasersystem, in accordance with a particular embodiment of the presentinvention.

FIG. 9 shows a distal end portion of an example multi-spot laser probeoperable to produce a multi-spot pattern of laser light beams, inaccordance with a particular embodiment of the present invention.

FIG. 10 shows a distal end portion of another example multi-spot laserprobe in which a lens having convex ends is disposed between a distalend of a MCF and a protective window, in accordance with a particularembodiment of the present invention.

FIG. 11 is a side view of an exposed end of an example multi-spot laserprobe showing the exposed end of a MCF aligned with a lens, inaccordance with a particular embodiment of the present invention.

FIG. 12 shows the exposed end of a MCF misaligned with a lens as aresult of an annular gap formed between the MCF and an inner wall of acannula.

FIG. 13 shows a ring that is disposed within an annular gap formedaround an inner cladding of a MCF at an exposed end thereof, inaccordance with a particular embodiment of the present invention.

FIG. 14 shows a cannula of another example multi-spot laser probe thatincludes a counterbore, in accordance with a particular embodiment ofthe present invention.

FIG. 15 shows an example multi-spot laser probe in which alignment of anexposed end of a MCF is provided by a reduced inner diameter of acannula, in accordance with a particular embodiment of the presentinvention.

FIG. 16 illustrates a potential risk of damage to a distal end of a MCFduring assembly, in accordance with a particular embodiment of thepresent invention.

FIGS. 17 and 18 illustrate formation of a necked down portion of acannula of an example multi-spot laser probe to maintain alignment of adistal end of a MCF and a lens, in accordance with a particularembodiment of the present invention.

FIG. 19 illustrates example operations for producing a multi-spot laserprobe, in accordance with a particular embodiment of the presentinvention.

DETAILED DESCRIPTION

In the following description, details are set forth by way of example tofacilitate an understanding of the disclosed subject matter. It shouldbe apparent to a person of ordinary skill in the field, however, thatthe disclosed implementations are exemplary and not exhaustive of allpossible implementations. Thus, it should be understood that referenceto the described example is not intended to limit the scope of thedisclosure. Any alterations and further modifications to the describeddevices, instruments, methods, and any further application of theprinciples of the present disclosure are fully contemplated as wouldnormally occur to one skilled in the art to which the disclosurerelates. In particular, it is fully contemplated that the features,components, and/or steps described with respect to one implementationmay be combined with the features, components, and/or steps describedwith respect to other implementations of the present disclosure.

The present disclosure describes illuminating and non-illuminatingmulti-core laser probes and systems and methods associated therewith.FIG. 1 illustrates an example system 100 for creating a multi-spotpattern of laser light beams, according to certain embodiments.

System 100 includes a surgical laser system 102 that includes one ormore laser sources for generating laser beams that may be used during anophthalmic procedure. For example, the ophthalmic surgical laser system102 can alternatively generate a surgical treatment beam with a firstwavelength (e.g., ˜532 nanometers (nm)) and a laser aiming beam with asecond wavelength (e.g., ˜635 nm). A user, such as a surgeon or surgicalstaff member, can control the surgical laser system 102 (e.g., via afoot switch, voice commands, etc.) to alternatively emit the laseraiming beam and fire the treatment beam to treat patient anatomy, e.g.,perform photocoagulation. In some instances, the surgical laser system102 may include a port, and the laser beams may be emitted through theport in the surgical laser system 102. The surgical laser system 102 mayinclude a laser system port adaptor containing optical elements (notshown) for creating a multi-spot pattern of laser light beams from alaser light beam from the laser source.

System 100 can deliver the multiplexed light beam from the port to asurgical probe 108 via a multi-core optical fiber cable (MCF) 110. Probe108 may produce a multi-spot pattern of laser light beams to bedelivered to the retina 120 of a patient's eye 125. Probe 108 includes aprobe body 112 and a probe tip 140 that house and protect the MCF 110. Adistal end portion 145 of the probe tip 140 also contains a lens (notshown, described in greater detail below) that translates themultiplexed light beam from the distal end of the MCF 110 onto theretina 120.

Various systems and methods can be employed to create a multi-spotpattern of laser light beams and to multiplex the multi-spot pattern oflaser light beams with an illumination light beam. In some cases, a portadaptor may contain optical elements operable to create a multi-spotpattern and/or multiplex light beams. In some implementations, thesurgical laser system 102 may also include a female chimney port (notshown), and the port adapter may include a ferrule that functions as amale coupling for the female chimney port. The ferrule may include anopening that allows laser light from surgical laser system 102 to enterand one or more optical elements to collimate laser light received fromthe laser source. In some examples, the optical element in the ferrulemay be a graded-index (GRIN) lens with a length and a pitch selectedsuch that the optical element collimates laser light received at theopening of the ferrule at a selected distance adjacent to a diffractiveoptical element (DOE). In other examples, the optical element may be oneof several other types of lenses (e.g., spherical, aspherical, biconvexglass lens etc.). The DOE may focus a multi-spot pattern of laser lightbeams into an interface plane of a proximal end of an MCF such that eachof the laser light beams in the multi-spot laser pattern of laser lightbeams is propagated along an entire length of a selected core of aplurality of cores contained within the MCF, to a distal end of asurgical probe.

In operation, a laser source of surgical laser system 102 generates alaser light beam. Collimating optics in the surgical laser system 102collimate the laser light, which is directed to a diffractive opticalelement configured to create a multi-spot laser pattern of laser lightbeams. The multi-spot laser pattern is then directed to a condensinglens and focusing optics of the surgical laser system 102 to focus themulti-spot pattern onto an interface plane of a proximal end of an MCFsuch that each of the laser light beams in the multi-spot laser patternof laser light beams is propagated along an entire length of a selectedcore of a plurality of cores contained within the MCF 110. Themulti-spot pattern of laser light beams is transmitted by MCF 110 toprobe 108 disposed at a distal end of the MCF 110. The multi-spotpattern of laser light beams exits the MCF 110 and is transmittedthrough a lens at distal end portion 145 of the probe 108. Themulti-spot pattern of laser light beams exiting the probe 108 may beprojected onto the retina 120 of eye 125.

FIG. 2 illustrates embodiments of probe tip 140 of FIG. 1 in moredetail. As described above, the probe 108 includes a probe body 112shaped and sized for grasping by a user. Extending from the probe body112 is probe tip 140, which includes a sleeve 251 and a cannula 250. Asshown, cannula 250 is partially housed by and extends beyond the distalend of sleeve 251. In the illustrated example, the probe tip 140includes a straight portion 216 (e.g., sleeve 251 and a straight part ofcannula 250) and a curved portion 218 (e.g., the curved part of cannula250). In other implementations, the probe tip 140 may have other shapes.For example, in some instances, the probe tip 140 may be entirelystraight, include more than one curved portion, be entirely curved, orbe shaped in any desired manner.

Probe tip 140 may be formed of one or more materials including, forexample, stainless steel, titanium, Nitinol, and platinum. In someexamples, a first portion of probe tip 140 (e.g., the straight portion216) may include a first material and a second portion of probe tip 140(e.g., curved portion 218) may include a second material. In someinstances, the first material may be different from the second material.For example, in some instances, the first material may include stainlesssteel, e.g., tubular stainless steel, and the second material mayinclude Nitinol, e.g., tubular Nitinol. A distal end portion 145 of theprobe tip 140 may be inserted into an eye to perform a surgicalprocedure.

FIGS. 3 and 4 illustrate the distal end of an example MCF 300 (e.g.,similar to MCF 110) from different angles. The MCF 300 includes aplurality of cores 302 disposed in a cladding 304, which may be formedfrom fused silica. Laser light provided by a laser light source, such asthe surgical laser system 102, discussed above, may be split into aplurality of beams. Each of the beams is directed into one of the cores302 of the MCF 300. Thus, each of the cores 302 conducts one of thelight beams along the length of the MCF 300. In some implementations,the cores 302 may be constructed, e.g., from germanium-doped silica, andthe cladding 304 may be constructed from fused silica, such that thelaser light traveling along the cores 302 is contained within the cores302 and prevented from escaping from the cores 302 into the cladding304. For example, the refractive index of the one or more of the cores302 may be greater than the refractive index of the cladding 304.

Although four cores 302 are shown in the illustrated example, the scopeof the disclosure is not so limited. Rather, in other implementations,the MCF 300 may include fewer cores 302, while other implementations mayinclude more than four cores 302. In some implementations, the MCF 300may include two, four, or more inner cores 302, and, in some examples,the cores 302 may form a 2×2 array that matches a 2×2 multi-spot patterngenerated by a diffractive optical element that may be disposed in asurgical laser system, such as surgical laser system 102. A coating 306is formed over the cladding 304. In some instances, the coating 306 maybe a polyimide coating. In other instances, the coating 306 may beformed from other materials, such as acrylate. In some implementations,an index of refraction of the coating 306 may be greater than, lessthan, or the same as the index of refraction of the cladding 304.

In certain embodiments, the diameter of each core 302 may be about75+/−2 μm, the outer diameter of the cladding 304 may be about 295+/−5microns (μm), and the outer diameter of the coating 506 may be about325+/−5 μm. In certain embodiments, the centers of two adjacent cores302 may be about 126+/−5 μm from each other while the distance betweenthe centers of two cores 302 that are diagonal with respect to eachother may be about 178+/−5 μm.

In the example of FIGS. 3 and 4, the MCF 300 is a non-illuminating MCF.That is, while each of the cores 302 is adapted to conduct light, e.g.,laser light, the cladding 304 itself is not utilized to conduct a lightused for general illumination at the treatment site.

FIG. 5 shows an example of an illuminating MCF, shown as MCF 500. TheMCF 500 includes a plurality of cores 502 disposed in an inner cladding504, which may be formed from fused silica. The cores 502 operatesimilarly to the cores 302 described above. Although four cores 502 areshown in the illustrated example, the scope of the disclosure is not solimited. Rather, in other implementations, the MCF 500 may include fewercores 502, while other implementations may include more than four cores502. In some implementations, the MCF 500 may include two, four, or moreinner cores 502, and, in some examples, the cores 502 may form a 2×2array that matches a 2×2 multi-spot pattern generated by a diffractiveoptical element that may be disposed in a surgical laser system, such assurgical laser system 102. An outer cladding 506 is formed over theinner cladding 504. The MCF 500 also includes a coating 508 formed overthe outer cladding 506. Coating 508 may refer to a jacket. In someinstances, the outer cladding 504 and the coating 508 may be formed froma polymeric material.

An illuminating MCF is one in which light for general illumination, asopposed to targeted laser light for treatment, is transmitted throughthe cladding of the MCF in order to provide general illumination at atreatment site. Thus, the inner cladding 504 may be utilized to transmitlight therealong to provide general illumination, as opposed to laserlight for treatment, at a treatment site. In an illuminating MCF 500, anindex of refraction of the outer cladding 506 may be less than arefractive index of the inner cladding 504. The outer cladding 506,which may be a hard silica cladding, may be formed from a polymericmaterial that may not be stable at high temperatures. Therefore, aportion of the outer cladding 506 may be stripped or otherwise removedfrom the MCF 500 near an interface (e.g., about 0.5 to 5 mm) with alens, as described below, in order to improve the power handlingcapability of a probe in which the MCF 500 is included. In certainembodiments, the coating 508 is removed for a length of about 50millimeters (mm), measured from the distal end of MCF 500. This lengthmay correspond to the length of the cannula (e.g., cannula 250). Coating508 may be removed to allow MCF 500 to fit into the cannula because,with the coating 508 on, MCF 500 may have a larger outer diameter thanthe inner diameter of the cannula.

In certain embodiments, the diameter of each core 502 may be around75+/−2 μm, the outer diameter of the inner cladding 504 may be 295+/−5μm, the outer diameter of the outer cladding 506 may be 325+/−5 μm, andthe outer diameter of the coating 508 may be 425+/−30 μm. In certainembodiments, the centers of two adjacent cores 502 may be around 126+/−5μm from each other while the distance between the centers of two cores502 that are diagonal with respect to each other may be around 178+/−5μm.

FIG. 6 is a partial cross-sectional detailed view of the distal endportion 145 of the probe tip 140, shown in FIG. 2. Note that the distalend portion 145 of the probe tip 140 may also be the distal end portionof cannula 250. As described above, the probe tip 140, which includescannula 250, may be formed from one or more materials, such as, forexample, stainless steel, titanium, Nitinol, or platinum. An MCF 600,which may be an illuminating MCF (e.g., MCF 500, described above) ornon-illuminating MCF (e.g., MCF 300, described above), extends throughthe cannula 250 of the probe tip 140 and includes a plurality of cores602, which may operate similarly to cores 302 and 502 of FIGS. 3 and 5,respectively. In the illustrated example, the MCF 600 includes fourcores 602, although, as explained above, the MCF 600 may include feweror additional cores, for example, to provide a desired number of laserbeams. For the purposes of illustration, the MCF 600 is described as anon-illuminating MCF. However, the scope of the disclosure also includesilluminating MCFs.

A distal end portion 604 of the MCF 600 is disposed at the distal endportion 145 of the probe tip 140 and is described in more detail, below.The distal end portion 604 terminates at an interface 606 with a lens608. The interface 606 may be configured to translate a geometry of amultiplexed multi-spot laser pattern from the distal end of the MCF 600,through the lens 608, and onto a target surface, e.g., a tissue at atreatment site.

A portion of an outer cladding 610 of the MCF 600 is removed (e.g., bystripping), at a distal end 616 thereof, thereby exposing cladding 612.Consequently, at the interface 606, the cladding 612 of the MCF 600 isexposed. In some instances, the outer cladding 610 may be removed oromitted for a length L measured from a distal end 616 of the MCF 600 inorder to mitigate or eliminate thermal problems (e.g., temperaturebuild-up at the MCF 600 and lens 608 interface), thereby improvingperformance of the laser probe. For example, removal of the outercladding 610 at the interface 606 between the MCF 600 and the lens 608improves power handling characteristics of probe 108. That is, byremoval of the outer cladding 610, the power level of the laser lightpassing through the probe 108 may be greater than a power level of laserlight capable of being passed through the probe 108 if the outercladding 610 were not removed from the MCF 600 at the interface 606.Consequently, with the outer cladding 610 removed as described, a higherthermal loading of the probe 108, and particularly at the interface 606,is possible

In some instances, the length L may be within a range of 0.5 mm to 5.0mm. In some instances, the length L may be within a range of 1.0 mm to3.0 mm and any length therein. Particularly, in some instances, thelength L may be 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, or 3.0 mm. Further, thelength L may be any length in between these values. At the interface606, a distal end face 618 of the MCF 600 may abut the proximal end face614 of the lens 608. In other instances, the distal end face 618 of theMCF 600 may be offset from the proximal face 614 of the lens 608.

In certain implementations, the distal end face 618 formed at the distalend 616 of MCF 600 may abut the proximal end face 614 of the lens 608with positive pressure. In other implementations, the distal end face618 of the MCF 600 may be separated from the proximal end face 614 ofthe lens 608 by an air gap. In still other implementations, one or moreoptically transmissive elements or materials may be situated at theinterface 606 between the MCF 600 and the lens 608. In someimplementations, the lens 608 may be a GRIN lens, a spherical lens, oran aspherical lens. In still other implementations, the lens 608 may bea group of lenses formed of optically clear material.

The lens 608 may include one or more lenses formed from a visiblytransparent glass or ceramic. For example, the material used to form theone or more lenses of the lens 608 may include fused silica,borosilicate, or sapphire. In some implementations, the lens 608 mayinclude a single-element cylindrical GRIN rod lens that is operable toreceive one or more laser beams from distal end 616 of MCF 600 and relaythe received laser beams toward a distal tip 620 of the probe tip 140.In some instances, the distal tip 620 of the probe tip 140 may alsocorrespond to the distal end of the lens 608. In other instances, aprotective window may be disposed between the distal end of the lens 608and a distal tip 620 of the probe tip 140. In still otherimplementations, the window may extend from a distal tip 620 of theprobe tip 140.

While the MCF 600 is described in the context of being anon-illuminating type, the scope of the disclosure is not so limited.Rather, the concepts described herein are equally applicable toilluminating MCFs. Thus, the MCF 600 may be an illuminating MCF similarto the MCF 500 of FIG. 5.

FIGS. 7A-D, E1-E2, and F1-F2 compare embodiments of amulti-spot/multi-fiber laser probe with an MCF laser probe, as disclosedherein, to highlight various advantages and benefits of the MCF laserprobe. FIGS. 7A-7B illustrate multiple fibers 710 that may be used in amulti-spot/multi-fiber laser probe (not shown), where each of the fibers710 is used to conduct a single laser beam. More particularly, FIG. 7Aillustrates a front view of fibers 710 housed within a multi-lumen tube760 (e.g., a micro spacer). As shown, multi-lumen tube 760 comprisesfour tunnel-shaped passages or holes 716, each of which houses a fiber710. Adhesive 715 is used to bond each fiber 710 to its correspondinghole 716. FIG. 7B illustrates a side view of fibers 710 extending from acannula 750. Note that the multi-lumen tube of FIG. 7A is not shown inFIG. 7B.

As a general matter, it is difficult to control multiple individualfibers 710 with precision during manufacturing of amulti-spot/multi-fiber laser probe. Multi-spot/multi-fiber laser probedesigns can require precise alignment of multiple individual fibers 710in the internal diameter (ID) of a ferrule to receive the multiple laserbeams with the required high coupling efficiency. For example, apolyimide tube is used to manage multiple individual fibers 710, andeach fiber 710 is stripped individually, which can be time-consuming.After stripping, the multiple fibers 710 are inserted into correspondingholes in the multi-lumen tube 760, which can be difficult and slow.Further, the fibers 710 are cleaved individually, retracted back to thepolyimide tube and the multi-lumen tube 760, made flush by a stopper,and bonded together by UV during adhesive. The assembly then undergoessecondary heat curing to improve bonding stability at high temperature.This manufacturing process associated with the multi-spot/multi-fiberdesign is complicated and slow. Also the adhesive 715 used betweenindividual fibers and their corresponding holes or housings 716 in themulti-lumen tube 760 may be prone to thermal damage and can induce probefailure.

In contrast to FIGS. 7A and 7B, FIGS. 7C and 7D illustrate an MCF 720,similar to the MCFs 300, 500, and 600 shown in FIGS. 4-6. Moreparticularly, FIG. 7C illustrates a front view of MCF 720, whichcomprises a plurality of cores 702 embedded in a cladding 704, which iscoated by coating 724. FIG. 7D illustrates a side view of MCF 720extending from cannula 752. As shown, in contrast to the multiple fibers710 of a multi-spot/multi-fiber laser probe, MCF 720 is a single fiberhaving a plurality of cores 702, each transmitting a laser beam.

Laser probes incorporating an MCF, such as MCF 720, do not require theuse of adhesives between the cores 702, as the cores 702 are embedded ina cladding 704 and contained within a single optical fiber. As a result,laser probes comprising an MCF may have significantly improved powerhandling capabilities. Moreover, assembly of an MCF laser probe iscomparatively simple, as only a single fiber needs to be aligned andhandled during manufacturing. Accordingly, there is no need to use apolyimide tube and a multi-lumen tube to manage multiple individualfibers during assembly, and stripping a single MCF 720 takesconsiderably less time than stripping multiple individual fibers 710 ofa multi-spot/multi-fiber probe.

Further, utilizing an MCF in a laser probe may allow for tightlycontrolling the direction of the propagated beams. More specifically,using an MCF may ensure that the beams propagated by the laser probe aretightly controlled and not pointing towards the inner surface of thecannula. A comparison between a laser beam pattern associated withmultiple fibers of a multi-spot/multi-fiber laser probe and a laser beampatter associated with the cores of an MCF is illustrated in FIGS.7E1-E2 and 7F1-F2.

FIG. 7E1 depicts a fiber pattern at the distal end of a fiber assembly,including multiple fibers 710, within a multi-lumen tube 760. FIG. 7E2illustrates a laser beam pattern 770 including laser beam spots 772corresponding to the fiber pattern of FIG. 7E1. As shown, some of fibers710 (e.g., top and bottom right cores) are not centered within passages716 of the multi-lumen tube 760, which result in those fibers 710propagating beams that may be skewed outwardly, as shown in FIG. 7E2. Insome cases, some of fibers 710 may not be centered within theircorresponding passages 716 due to loose tolerance between the outerdiameter of the fibers 710 and the inner diameter of passage 716 of themulti-lumen tube 760, causing fibers 710 to point towards the innersurface of the cannula (not shown) instead. As a result, beamspropagated by fibers 710 also point towards the inner surface of thecannula, instead of being pointed in a straight direction and towards apatient's eye. This causes the beams to escape a lens, e.g., lens 608,of the laser probe and be absorbed by the inner surface of the cannula,which may cause the cannula to overheat. In addition, fibers 710 notbeing centered within their corresponding passages 716, result in anundesirable uniformity among the corresponding four beam spots.

In contrast to FIGS. 7E1-E2, FIGS. 7F1-F2 illustrate a fiber pattern anda beam pattern, respectively, associated with an MCF. FIG. 7F1illustrates cores 702 of an MCF that are pointing in a straightdirection and not skewed outwardly. This is because the cores 702 areembedded in the cladding tightly together. As a result, cores 702 areable to propagate beams spots 782, shown in beam pattern 782 of FIG.7F2, which are also pointed in a straight direction and not towards theinner surface of the cannula (not shown) within which the MCF is housed.As such, using an MCF improves control of the laser beam pattern (e.g.,a desirable uniformity among the four beam spots) of a laser probe andincreases the power handling by preventing the cannula from overheatingas a result of the beams pointing towards the inner surface of thecannula.

Thus, the disclosed MCF laser probe design may simplify manufacturing byeliminating complex and costly manufacturing requirements, improve powerhandling by eliminating adhesive failure or the introduction ofcontamination into the distal fiber assembly of a multi-fiber probeduring bonding of distal ends of multiple fibers, increase couplingefficiency by employing a precisely-aligned MCF and avoidingdifficulties associated with aligning individual fibers with multipleinput laser beams in a multiple-fiber assembly, and improve control ofthe laser beam pattern (which also further improves power handling).These and other advantages will be apparent to one skilled in the art inview of the present disclosure.

FIG. 8 illustrates example flow chart 800, which illustrates steps in amethod for applying a multi-spot laser beam pattern, in accordance witha particular embodiment of the present invention. In certainembodiments, operations 800 are performed by a system, such as surgicallaser system 102 of FIG. 1, which is coupled to an MCF laser probe, suchas MCF laser probe 108 of FIG. 1.

At block 802, the system generates a laser light beam by a laser source.As described above, the laser source may be a part of or be coupled tosurgical laser system 102.

At block 804, the system collimates the laser light beam. A collimatedlaser light beam refers to a laser light beam having parallel rays.

At block 806, the system directs the collimated laser light beam to adiffractive optical element (DOE) configured to create a multi-spotlaser pattern of laser light beams. DOEs, as one of ordinary skill inthe art recognizes, are used for shaping and splitting laser lightbeams.

At block 808, the system directs the multi-spot pattern of laser lightbeams to a condensing lens.

At block 810, the system focuses the multi-spot pattern of laser lightbeams into an interface plane of a proximal end of an MCF such that eachof the laser light beams in the multi-spot laser pattern of laser lightbeams is transmitted into one of a plurality of cores of the MCF andpropagated there along, the plurality of cores being surrounded by acladding and the cladding being surrounded by a coating, a refractiveindex of each of the plurality of cores being greater than a refractiveindex of the cladding, and a portion of the coating being omitted from alength of a distal end of the MCF.

For example, surgical laser system 102 focuses the multi-spot pattern oflaser light beams into an interface plane of a proximal end of an MCF(e.g., MCF 110, MCF 300, MCF 500, MCF 600, etc.) such that each of thelaser light beams in the multi-spot laser pattern of laser light beamsis transmitted into one of a plurality of cores (e.g., cores 302, 502,602, etc.) of the MCF and propagated there along, the plurality of coresbeing surrounded by a cladding (e.g., cladding 304, 504, 506, 612, etc.)and the cladding being surrounded by a coating (e.g., 306, 508, etc.), arefractive index of each of the plurality of cores being greater than arefractive index of the cladding, and a portion of the coating beingomitted from a length (e.g., shown as length L in FIG. 6) of a distalend of the MCF.

At block 812, the system transmits the multi-spot pattern of laser lightbeams to the distal end of the MCF. For example, the system transmitsthe multi-spot pattern of laser light beams to the distal end (e.g.,distal end 616) of the MCF.

At block 814, the system directs the multi-spot pattern of laser lightbeams through a lens (e.g., lens 608) at a distal tip (e.g., distal tip620) of a surgical probe (e.g., probe 108).

FIG. 9 shows a distal end portion of another example probe 901 operableto produce a multi-spot pattern of laser light beams. The illustratedexample probe 901 includes an illuminating MCF 900, which may be similarto the MCF 500 described above. Consequently, the probe 901 is operableto emit both general illumination for illuminating a surgical field aswell as a plurality of laser beams for treating a treatment site, e.g.,a retina. The probe 901 may be similar in many respects to the probe108. As shown, the probe 901 includes a cannula 902. The cannula 902includes an inner surface 936 that defines an inner passage 942. The MCF900 extends through at least a portion of the cannula 902 up to a firstinterface 906 with a lens 908. The MCF 900 may abut the lens 908 or agap, e.g., an air-filled gap, may be disposed between a distal end 916of the MCF 900 and a proximal end 914 of the lens 908. In someinstances, the distal end 916 of MCF 900 may abut the proximal end 914of the lens 908 with positive pressure. In some instances, the lens 908may be formed from fused silica, borosilicate, or sapphire. In someinstances, the lens 908 may be a spherical lens. The lens 908 may be aGRIN lens, such as a single-element cylindrical GRIN rod lens that isoperable to receive one or more laser beams from distal end of MCF 900and relay the received laser beams toward a distal tip 920 of the probe901.

The probe 901 also includes a protective window 918 extending from asecond interface 922 with the lens 908. As shown in FIG. 9, theprotective window 918 abuts the lens 908. In other implementations, agap, e.g., an air-filled gap, may exist between the protective window918 and the lens 908. In the illustrated example, the protective window918 extends distally beyond a distal end 924 of the cannula 902, and adistal end 926 of the protective window 918 defines the distal tip 920of the probe 901. In other implementations, the distal end 926 of theprotective window 918 may be aligned with the distal end of the distalend 924 of the cannula 902 such that the distal end 924 of the cannula902 and the distal end 926 of the protective window 918 aresubstantially flush. One of ordinary skill in the art recognizes thatthe relative positions of the end surface of the distal end 924 of thecannula 902 and the end surface of the distal end 926 of the protectivewindow 918 may vary slightly due to manufacturing tolerances.

The protective window 918 may be formed from an optically stable andhigh temperature resistant material. In some instances, the protectivewindow 918 may be formed from sapphire or quartz. In some instances, theprotective window 918 may have a flat proximal end surface, as shown inFIG. 9. In other instances, the protective window 918 may have a convexproximal end surface 928. An example of such a lens is shown in FIG. 10.

In FIG. 10 lens 1008 has convex proximal and distal ends. Although thelens 1008 is elongated in the longitudinal direction, in other examples,it may instead be a spherical or ball lens. In some implementations, alens having a flat proximal end and/or a flat distal end, such as thelens 908 shown in FIG. 9, may be used in combination with a protectivewindow 1018 that has a convex proximal end, similar to that shown inFIG. 10. In still other implementations, a probe may include a lens thatincludes a convex proximal end and/or a convex distal end, e.g., aspherical lens or a lens such as that shown in FIG. 9, in combinationwith a protective window having a flat proximal end, such as theprotective window 918 shown in FIG. 9.

Referring back to FIG. 9, the MCF 900 includes an outer cladding 930,which may be similar to the outer cladding 506 shown in FIG. 5. Theouter cladding 930 is removed, e.g., stripped, from the inner cladding932 for a length L measured and extending proximally from the distal end916 of the MCF 900, thereby exposing the underlying inner cladding 932.

In some instances, the length L may be within a range of 0.5 mm to 5.0mm. In some instances, the length L may be within a range of 1.0 mm to3.0 mm and any length therein. Particularly, in some instances, thelength L may b 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, or 3.0 mm. Further, thelength L may be any length in between these values. As explained above,removal of a portion of the outer cladding may improve the thermalhandling properties of the probe, such that a power level of the laserenergy transmitted through the probe may be increased. A portion ofcores 933 extending through the inner cladding 932 is shown.

However, with a portion of the outer cladding 930 removed, an annulargap 934 exists between the inner cladding 932 and the inner surface 936of the cannula 902. The annular gap 934 introduces a risk ofmisalignment between the MCF 900 and the lens 908 (i.e., the MCF 900 maybecome decentered from the lens 908). FIG. 11 is a side view of anexposed end 938 of the probe 901, wherein the exposed end 938 of the MCF900 is aligned with the lens 908. The exposed end 938 of the MCF 900 isthe portion of the MCF 900 from which the outer cladding 930 is removed.

FIG. 12, however, shows the exposed end 938 of the MCF 900 misalignedwith the lens 908 as a result of the annular gap 934. As shown in FIG.12, the exposed end 938 of the MCF 900 is not concentric with the lens908. With the exposed end 938 of the MCF 900 misaligned with the lens908, the resulting laser spot and illumination beam pattern are nolonger concentric with the cannula 902. This misalignment between theMCF 900 and the lens 908 may also result in a portion of the light thatis propagated for general illumination purposes and passes through theinner cladding 932 to strike the inner wall 936 of the cannula 902. Thisdecreases the illumination efficiency of the probe 901 and results in anundesirable illumination pattern.

In certain embodiments, in order to maintain alignment between the MCF900 and the lens 908, a ring formed from thermally-stable material maybe disposed in the annular gap 934 to maintain concentricity of the MCF900 with the inner passage of the cannula and the lens. In certainembodiments, the material may include e.g., polyimide, metal, stainlesssteel, nickel, silver, copper, brass, etc. Although polyimides andmetals are possible materials from which the ring may be made, othermaterials may also be used. An example of a ring used for maintainingalignment between the MCF 900 and the lens 908 is illustrated in FIG.13.

FIG. 13 illustrates a ring 940 disposed within the annular gap 934formed around the inner cladding 932 at the exposed end 938 of the MCF900. The ring 940 maintains concentricity of the MCF 900 and the lens908, e.g., by restricting lateral movement of the exposed end 938 of theMCF 900. In some instances, the inner diameter of the ring 940corresponds to the outer diameter of the exposed end 938 of the MCF 900.In some instances, an outer diameter of the ring 940 corresponds to aninner diameter of the inner passage 942. The ring 940 may span theentire length L of the exposed end 938 or less than the entire length L.

FIG. 14 shows another example implementation for maintaining alignmentof the MCF 900 and the lens 900. In the example shown in FIG. 14, thecannula 1402 includes an inner passage 942 having a first inner diameter1444 that conforms more closely to the outer diameter of the MCF 900.The cannula 1402 also includes a counter-bore 946 having a second innerdiameter 1448 larger than the first inner diameter 1444. Thecounter-bore 946 is provided in order to accommodate the lens 908 andthe protective window 918, if included, within the cannula 1402 due tothe larger transverse cross-sectional sizes of these components ascompared to the transverse cross-sectional size of the MCF 900.Therefore, along the exposed end 938, the passage 942 having a reducedcross-sectional size compared to the counterbore 946 is capable ofmaintaining alignment of the exposed end 938 of the MCF 900 with thelens 908 to a better degree than if the inner diameter 1444 of passage942 were the size of the inner diameter 1448 of the counter-bore 946. Asa result, alignment between the MCF 900 and lens 908 is improved. Insome instances, the counter-bore 946 extends proximally from the distalend of the cannula 1402.

FIG. 15 shows an example in which alignment of the exposed end 938 ofthe MCF 900 is provided by a reduced inner diameter 1550 of the cannula1502. The reduced diameter 1550 is provided by a necked down portion1552 of the cannula 1502, which may be the result of a crimp. Thereduced inner diameter 1550 may be made to correspond to the outerdiameter of the exposed end 938 of the MCF 900. The reduced innerdiameter 1550 maintains alignment of the exposed end 938 with the lens908, thereby achieving improved general illumination performance andalignment of the laser spot pattern with the longitudinal axis of thecannula 1502.

FIG. 16 illustrates a potential risk for introduction of damage to theMCF 900 during assembly of a multi-spot laser probe in the context ofthe design shown in FIG. 15. If the necked down portion 1652 of thecannula 1602, such as generated by a crimp applied to the cannula 1602,is formed prior to the introduction of the MCF 900 into necked downportion 1652, there is a risk of damage to the distal end 1654 (andparticularly to the edge 1656 of the distal end 1654) of the MCF 900,when insertion of the distal end 1654 through the necked down portion1652 is attempted. Misalignment of the distal end 1654 with the neckeddown portion 1652 during assembly may produce forces that can chip anddamage the distal end 1654 of the MCF 900. Even small loads applied tothe distal end 1654, and particularly to the edge 1656 thereof, canproduce damage, such as chipping of the distal end 1654 and edge 1656,that results in an impaired performance whether in poor generalillumination or an imprecise or distorted laser spot pattern or both.Such damage may render the resulting laser probe unusable. As a result,a necked down portion may be formed in a cannula after introduction ofan MCF into the cannula, as shown in FIGS. 17 and 18.

FIGS. 17 and 18 show the distal end 1654 of the MCF 800 abutting thelens 908 at the first interface 906. However, as explained above, a gapmay be disposed between the distal end 1654 of MCF 800 and the lens 908.In some implementations, one or both of the lens 908 and window 918 maybe installed in the cannula 1702 prior to the assembly of the MCF 900.In some implementations, the MCF 900 may be installed prior to one orboth of the lens 908 and window 918.

With the MCF 900 positioned within the cannula 1702 at a desiredposition, the necked down portion 1752 may be formed in the cannula1702, such as by crimping. The necked down portion 1752 maintains theexposed end 938 of the MCF 900 concentric with the lens 908. As aresult, the risk of the distal end 1654 of the MCF 900 being damaged bythe necked down portion 1752 is eliminated.

In some instances, the necked down portion 1752 is a reduced annulusentirely encircling the exposed end 938 of the MCF 900. As a result, thenecked down portion 1752 defines a reduced diameter 1858 of the innerpassage 942 that conforms to the outer diameter of the exposed end 938.In some instances, the reduced diameter 1858 of the necked down portion1752 is the same as or slightly larger than the outer diameter of theexposed end 938. As an example, a 5 μm annular gap may be formed betweenthe inner surface of the cannula 1702 at the necked down portion 1752and the outer surface of the exposed end 938. In some embodiments, theexposed end 938 may contact the inner surface of the necked down portion1752 at one or more locations.

In certain embodiments, the necked down portion 1752 may formdiametrically opposed protrusions at one or more locations around thecircumference of the cannula 1702, thereby centering the exposed end 938of the MCF 900 with the lens 908. For example, in some instances, thenecked down portion 1752 may include two sets of diametrically opposedprotrusions offset 90° from each other. In certain otherimplementations, three or more non-diametrically opposed protrusions maybe formed in the cannula to center the exposed end 938 of the MCF 900.In some instances, the protrusions may be formed along a commoncircumference of the cannula 1702. In other implementations, one or moreof the protrusions may be longitudinally offset from one or more of theother protrusions.

Further, although the MCF 900 is described as an illuminating MCF, insome implementations, the MCF 900 may be non-illuminating MCF and remainwithin the scope of the disclosure.

FIG. 19 illustrates example flow chart 1900, which illustrates steps ina method for producing a multi-spot laser probe, in accordance with aparticular embodiment of the present invention.

At block 1902, a probe tip is provided, which comprises a cannulaconfigured for insertion into to an eye. For example, a technician or amachine may provide probe tip 901 having cannula 1702, as shown in FIG.18.

At block 1904, a lens is inserted into the cannula. For example, lens908 is inserted into cannula 1702.

At block 1906, an MCF is inserted into the cannula proximal to the lens.For example, MCF 900 is inserted into cannula 1702 proximal to lens 908,the MCF 900 comprising a plurality of cores 933. As shown, MCF 900comprises cladding 932, shown at the exposed end 938 of MCF 900.

At block 1908, a necked down portion is formed in the cannula, thenecked down portion forming a reduced cross-sectional size thatmaintains the exposed portion of the MCF centered within the cannula.For example, the necked down portion 1752 is formed in the cannula 1702.

Although several of the figures described herein show probes havingprotective windows, it is understood that the protective windows may beomitted. It is further within the scope of the present disclosure thatthe ends of the lens and/or protective windows may be a shape other thanflat. For example, one or more of the distal and proximal ends of thelens and protective window may have a convex shape, as described herein.

The above disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments which fall within thetrue spirit and scope of the present disclosure. Thus, to the maximumextent allowed by law, the scope of the present disclosure is to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing detailed description.

What is claimed is:
 1. A multi-spot laser probe comprising: a probe bodyshaped and sized for grasping by a user; a probe tip comprising acannula configured for insertion into an eye; a graded-index (GRIN) lensdisposed in the cannula at a distal end portion thereof; a multi-coreoptical fiber cable (MCF) extending at least partially through thecannula, the MCF comprising: a plurality of cores formed ofgermanium-doped silica; a cladding formed of fused silica, the claddingsurrounding the plurality of cores, a refractive index of one or more ofthe plurality of cores being greater than a refractive index of thecladding; a coating surrounding the cladding; and a distal end disposedat an interface with the GRIN lens, a portion of the coating beingomitted from a length of the distal end of the MCF, and the GRIN lensconfigured to translate laser light from the distal end of the MCF tocreate a multi-spot pattern of laser beams on a target surface.
 2. Themulti-spot laser probe assembly of claim 1, wherein the plurality ofcores form a 2×2 array configured to match a 2×2 multi-spot pattern froma diffractive optical element (DOE) of a laser system.
 3. The multi-spotlaser probe assembly of claim 2, wherein the distal end of the MCF abutsthe GRIN lens with positive pressure at the interface.
 4. The multi-spotlaser probe assembly of claim 2, wherein the distal end of the MCF isseparated from the GRIN lens by an air gap.
 5. The multi-spot laserprobe of claim 1, wherein a length of the portion of the coating removedfrom the MCF is in a range of 0.5 mm to 5.0 mm extending proximally fromthe distal end of the MCF.
 6. The multi-spot laser probe of claim 5,wherein the length of the portion of the coating removed from the MCF isin a range of 0.1 mm to 3.0 mm extending proximally from the distal endof the MCF.
 7. The multi-spot laser probe of claim 1, furthercomprising: a second cladding surrounding the cladding, the secondcladding comprises polymer, wherein the coating surrounds the secondcladding, the coating comprising polymer.
 8. A multi-spot laser probecomprising: a multi-core optical fiber cable (MCF) comprising aplurality of cores surrounded by a cladding and a coating surroundingthe cladding, wherein a refractive index of one or more of the pluralityof cores is greater than a refractive index of the cladding; a probecomprising a probe tip coupled with a distal end of the MCF; and a lenslocated at a distal end of the probe tip, wherein: the lens isconfigured to translate laser light from the distal end of the MCF tocreate a multi-spot pattern of laser beams on a target surface; and thedistal end of the MCF terminates at an interface with the lens.
 9. Themulti-spot laser probe assembly of claim 8, wherein: the coatingcomprises a polyimide coating; the plurality of cores comprisegermanium-doped silica; and the cladding comprises fused silica.
 10. Themulti-spot laser probe of claim 8, wherein a portion of the coating isomitted from a length of the distal end of the MCF.
 11. The multi-spotlaser probe of claim 10, wherein the length is in a range of 1.0 mm to3.0 mm.
 12. The multi-spot laser probe assembly of claim 8, wherein theplurality of cores forms a 2×2 array that is configured to match a 2×2multi-spot pattern from a diffractive optical element (DOE) of a lasersystem.
 13. The multi-spot laser probe of claim 8, wherein the probe tipcomprises a cannula configured for insertion into an eye, and whereinthe distal end of the MCF and the lens are disposed in the cannula. 14.The multi-spot laser probe of claim 8, wherein the lens comprises agraded-index (GRIN) lens and wherein the distal end of the MCF abuts theGRIN lens with positive pressure.
 15. The multi-spot laser probe ofclaim 8, wherein the lens comprises a graded-index (GRIN) lens andwherein the distal end of the MCF is separated from the GRIN lens by agap.
 16. The multi-spot laser probe of claim 8, wherein the probe tipcomprises a cannula configured for insertion into an eye, wherein thedistal end of the MCF and the lens are disposed in the cannula, whereina portion of the coating at the MCF is omitted, thereby improving powerhandling characteristics of the multi-spot laser probe, and wherein theplurality of cores forms a 2×2 array configured to match a 2×2multi-spot pattern from a diffractive optical element (DOE) of a lasersystem.
 17. The multi-spot laser probe of claim 8, wherein the lenslocated at a distal end of the probe tip comprises a graded-index (GRIN)lens.
 18. The multi-spot laser probe of claim 17, wherein the distal endof the MCF abuts the GRIN lens with positive pressure.
 19. Themulti-spot laser probe of claim 17, wherein the distal end of the MCF isseparated from the GRIN lens by an air gap.
 20. The multi-spot laserprobe of claim 8, further comprising: a second cladding surrounding thecladding, the second cladding comprises polymer, wherein the coatingsurrounds the second cladding, the coating comprising polymer.
 21. Amethod of applying a multi-spot laser beam pattern, the methodcomprising: generating a laser light beam by a laser source; collimatingthe laser light beam; directing the collimated laser light beam to adiffractive optical element (DOE) configured to create a multi-spotlaser pattern of laser light beams; directing the multi-spot pattern oflaser light beams to a condensing lens; focusing the multi-spot patternof laser light beams into an interface plane of a proximal end of amulti-core optical fiber cable (MCF) such that each of the laser lightbeams in the multi-spot laser pattern of laser light beams istransmitted into one of a plurality of cores of the MCF and propagatedthere along, the plurality of cores being surrounded by a cladding andthe cladding being surrounded by a coating, a refractive index of eachof the plurality of cores being greater than a refractive index of thecladding, and a portion of the coating being omitted from a length of adistal end of the MCF; transmitting the multi-spot pattern of laserlight beams to the distal end of the MCF; and directing the multi-spotpattern of laser light beams through a lens at a distal tip of asurgical probe.
 22. The method of claim 21, wherein: the plurality ofcores form a 2×2 array configured to match a 2×2 multi-spot patterngenerated by a diffractive optical element (DOE), the coating comprisesa polyimide coating, the plurality of cores comprise germanium-dopedsilica, the cladding comprises fused silica, and the lens comprises agraded-index (GRIN) lens.
 23. The method of claim 21, wherein a secondcladding surrounds the cladding, the second cladding comprises polymer,and wherein the coating surrounds the second cladding, the coatingcomprising polymer.